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This story was originally published October 14, 2022. It has been updated with new information.

What you need to know

  • Bivalent vaccines are now available for kids as young as 6 months old, either as a booster or as the third shot of their primary series.
  • The updated vaccines have no safety concerns and have been shown to increase protection against symptomatic infection in adults.
  • So far, uptake of bivalent vaccines as boosters has been low across age groups, with less than one-third of the 65 and older population vaccinated with an updated booster.

The CDC expanded the use of Pfizer’s and Moderna’s bivalent vaccines to kids as young as 6 months old on Friday, following FDA authorization the day before. Kids under 5 can now get a bivalent vaccine either as a booster or as the third shot of their primary series.

Bivalent vaccines—designed to protect against two COVID-19 variants—have been available to kids 5 and older as boosters since October, but so far less than 3 percent of kids 5 to 11 have gotten an updated booster and less than one-third of kids in this age group have completed their primary series.

Why do kids need a bivalent booster?

The updated boosters are bivalent vaccines that target the original COVID-19 strain and the BA.4 and BA.5 Omicron subvariants. They are designed to provide better protection against BA.5 and potentially against future variants. Recent real-world data shows that the updated boosters increase protection against symptomatic infection from COVID-19.

As winter approaches, indoor activities will increase and viruses will become more common. One of the best ways to keep kids protected against COVID-19 is to get them vaccinated and boosted. Keeping kids up to date on vaccines will help limit transmission, preventing more vulnerable family and community members from getting infected during the holiday season.

When can kids receive a bivalent booster?

As is the case for adults, kids as young as 5 can receive an updated booster at least two months after completing their primary series or receiving their first booster. Everyone still needs to receive the original vaccines for their primary series.

For younger kids, the guidance is a little more complicated. Kids under 6 who completed Moderna’s two-dose primary series can get Moderna’s bivalent booster two months after their last shot. Kids under 5 who started Pfizer’s three-shot primary series can get Pfizer’s bivalent vaccine for their third shot, but not as a booster (fourth shot). Pfizer’s bivalent vaccine for kids under 5 is not yet authorized as a booster.

Are the bivalent vaccines safe and effective?

Pfizer’s and Moderna’s bivalent vaccines have no safety concerns. In terms of efficacy, both laboratory and real-world data have shown that the updated vaccines increase protection against symptomatic infection, making them crucial to minimizing a winter surge.

Some parents may have concerns around the fact that the updated vaccines did not go through human trials. In developing the bivalent vaccines, scientists at both companies kept the original vaccines’ foundations and modified them slightly to include the BA.4 and BA.5 components. Because changes were minimal, the FDA did not need additional human trials to confirm safety and efficacy. This fast-tracked authorization process is similar to the one used for annual flu vaccines.

Should my child still get a bivalent vaccine if they just got boosted in the spring or summer?

In most cases, yes. The CDC recommends kids as young as 6 months get a bivalent booster at least two months after completing their primary series or receiving their first booster, though there is an exception for kids under 5 who received Pfizer’s primary series.

Some experts recommend waiting longer to get a booster—about four to six months—in order to maximize the immune response. They also recommend waiting about three months after COVID-19 infection to get your next dose. But it can be risky to wait or try to time your booster to the next surge as the virus is unpredictable and protection from the shot takes a few weeks to kick in. Generally speaking, it’s better to get a booster sooner rather than later, especially if you want to ensure protection for the holiday season.